
<!doctype html>
<html lang="en">
<head>
	<meta charset="UTF-8" />
	<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1" />
	<script type="text/javascript" src=""></script>
	<title> 页面名称 </title>
<style type="text/css">
#box {
	position: relative;
	width: 500px;
	height: 500px;
	border: 1px solid #999;
}
#box div {
	position: absolute;
	width: 20px;
	height: 20px;
	top: 0px;
	left: 0px;
	background-color: #f00;
	transition: all 500ms;
}
</style>
</head>
<body>

<div id="box">
	<div></div>
	<div></div>
</div>
<script type="text/javascript">
var div = document.getElementById("box").getElementsByTagName("div");
setInterval(function(){
	for (var i = 0; i < div.length; i++) {
		div[i].style.left = Math.floor(Math.random()*480)+"px";
		div[i].style.top = Math.floor(Math.random()*480)+"px";
	}
}, 500);
</script>
</body>
</html>